The concept of apparatus for removing materials from the interior of conveying apparatus generally involves pulsing air jets into the container to dislodge the materials from the rigid sidewall of the container. One of the drawbacks of the prior art is that unless the air jets are distributed throughout the system, the air jets may not be able to dislodge all the materials on the rigid sidewalls. The present invention provides a liner that can be pulsed to cause the liner to flex back and forth thus dislodging any material adhering to the liner through the undulation and vibrations of the flexible liner.